This invention relates to construction vehicles of the type having a material handling implement, and more particularly, to an improved stabilizer arm assembly for laterally supporting the vehicle and raising the wheels of the vehicle off the ground during operation of the material handling implement.
Many types of construction vehicles have stabilizer arms, or outriggers, which extend downwardly and outwardly from the frame sides during operation of their material handling implements to engage the ground to laterally support the vehicle against tipping, and to anchor the vehicle to the ground by raising the wheels at the end of the vehicle having the material handling implement off the ground. For example, in a vehicle having a material handling implement, such as a backhoe, operatively connected to the rear end of the vehicle, a stabilizer arm is positioned generally adjacent and rearwardly of each of the rear wheels. It has also been found advantageous under some working conditions to mount stabilizer arms at the front end of the vehicle. U.S. Pat. Nos. 3,376,984; 3,951,281; 3,955,695 and 4,026,428 disclose some typical arrangements of stabilizer arms.
A stabilizer arm typically has one end pivotally connected to the frame about a fixed stabilizer pivot point for movement between a ground engaging support position extending laterally outward of the wheel and a generally upright, transport or storage position. To move the stabilizer arm between support and transport positions and to apply a downward force on the stabilizer arm when in the support position to lift the vehicle off the ground, various power sources can be used. A common power source used for construction vehicles is a fluid ram, such as a hydraulic cylinder and piston rod assembly. Usually, one end of the fluid ram is pivotally mounted to the frame of the vehicle about a fixed pivot axis and the other end operatively connected to the stabilizer arm.
The lifting capability of a stabilizer assembly in a ground engaging position is proportional to the distance between the fixed stabilizer pivot point and the fluid ram centerline. This distance, or moment arm, is limited in prior art units having fixed frame-mounted fluid rams so as to tuck the stabilizer arms close to the frame sides in a generally upright position for transport.
It is therefore desirable to provide an improved stabilizer assembly which overcomes this limitation of the moment arm in prior art assemblies without sacrificing any degree of transport position uprightness.